This invention relates to the field of microwave ovens and ranges, and more particularly to the field of energy seals to prevent the escape of microwave energy from the oven cavity. The invention is particularly well suited to combination cooking ranges wherein food may be cooked by the simultaneous application of both thermal and microwave energy.
Existing government standards require that leakage of microwave energy from microwave cooking appliances be kept to minimum levels. General oven design parameters seek to eliminate spaces through which microwave energy can escape beyond the cooking cavity.
Prior art microwave ovens and ranges have incorporated some type of energy deflector or stirrer located within the microwave energy field for the purpose of breaking up static patterns and providing for a more uniform energy distribution within the oven. Such deflectors or stirrers are often rotatable and require some type of motor for operation, which motor is normally mounted outside of the microwave energy field. In such applications, the motor is typically mounted directly to the exterior side of one oven wall, effectively blocking the aperture through which the motor shaft extends into the cavity, thereby preventing leakage at that point.
In some microwave ovens designs it is not practical to mount a stirrer motor directly to a cavity wall. In such cases, excessive microwave leakage can occur at the point where the motor shaft passes through the cavity wall. This problem can arise in the design of a combination cooking range wherein food may be cooked by the simultaneous application of both thermal energy and microwave energy. The use of thermal energy causes the oven walls to be heated to an extent that the stirrer motor cannot be mounted directly to an oven wall.